War, Jihad, and the Defense of the Community

Ibn Taymiyyah's discussion of war and jihad in Al-Siyasah al-Shar'iyyah is shaped directly by the historical circumstances of his time: the Mongol invasions and the continued Crusader presence in the Levant. He writes as a scholar who participated in the defense of his community and who saw the theoretical questions of defensive war answered in immediate, practical terms by the situation on the ground.

The Obligation of Jihad

Ibn Taymiyyah treats jihad in the military sense as a collective obligation (fard kifayah) that becomes an individual obligation (fard ayn) when the Muslim community is under direct attack. The latter condition was, in his view, clearly fulfilled in his era — first by the Mongol invasion of Syria and later by the continued Crusader occupation of parts of the Levant. In such circumstances, every capable Muslim in the affected region is obligated to participate in defense, and the obligation extends to neighboring regions if the local defenders are insufficient.

He addresses the question of fighting Mongol rulers who had nominally converted to Islam but continued to govern by Mongol customary law (yasa) rather than Islamic law. Ibn Taymiyyah's famous legal opinions on this matter — that such rulers were to be treated as apostates or rebels rather than legitimate Muslim authorities — had far-reaching consequences for subsequent Islamic political thought, particularly in the twentieth century.

The Conduct of War

Al-Siyasah al-Shar'iyyah contains an extensive treatment of the Islamic rules governing the conduct of war (ahkam al-jihad). Ibn Taymiyyah draws on the Quran and Sunnah to establish the prohibitions: the prohibition on killing non-combatants (women, children, the elderly, monks, and farmers who are not fighting), the prohibition on mutilation of the dead, the rules governing prisoners of war, and the treatment of conquered populations.

He presents these rules not as constraints imposed from outside Islamic ethics but as expressions of the Islamic ethical vision itself: war is permitted for legitimate purposes (defense of the community, removal of oppression, protection of the vulnerable), and these purposes define its limits. A war that degenerates into indiscriminate killing, looting, and destruction has departed from its legitimate basis and becomes mere aggression.

The Commander's Obligations

A substantial section addresses the religious and administrative obligations of military commanders. The commander must maintain discipline among his troops, ensuring they observe the Islamic rules of warfare and do not commit prohibited acts against civilians or captives. He must be just in the distribution of spoils, following the Quranic formula (8:41) that assigns one-fifth to the public treasury and divides the remainder among the fighters. He must maintain the loyalty of his troops through fair treatment and proper provisioning.

Ibn Taymiyyah is insistent that military commanders are accountable to Islamic law even in the heat of war. The necessities of warfare do not suspend the law — they require its careful application under difficult conditions. A commander who orders or permits atrocities against civilians commits a sin that war does not excuse, and scholars have an obligation to speak against such conduct even when doing so is politically or personally dangerous.